This invention relates to improvements of a sound insulating wall which is erected along a road such as an expressway where a lot of noise is produced, and of a method of installing the sound insulating wall.
Conventionally, a sound insulating wall is constructed as follows: H-section steel bars are vertically placed at certain intervals (usually 2 to 4 m) on a footing, such as a railing, erected along an expressway or the like with their flanges faced with each other, and concrete boards (usually 2 m in width and 0.5 m in height) or unit boards (usually 4 m in width and 1 m in height) formed by combining a metal frame with a sound absorbing material or a plastic plate are set between the erected H-section steel bars by sliding them down through their flanges.
Hence, in an installation site of the sound insulating wall, it takes much labor to erect a number of H-section steel bars and to sliding down the unit boards or concrete boards through the flanges of the H-section steel bars. The sound insulating wall thus constructed is not smooth nor continuous in external appearance because the H-section steel bars appear at intervals of 2 to 4 m, and is very monotonous and drab. That is, unavoidably the sound insulating wall does not match the concrete road. On the other hand, the unit boards may be made dirty by wind, rain or dust. In order to clean those unit boards, it is necessary to disengage them from the H-section steel bars, and engage them again with the latter after being cleaned. This work not only takes much labor but is also hazardous to workers.